There is a wide variety of nut drive wrenches. For example, U.S. Pat. No. 6,708,778, describes a hydraulic unit including case, a liner contained in the case, and a top cap and an opposing bottom cap plugged at the front and rear ends of the case. The unit further includes a spindle disposed in the liner and provided with a large diameter section. The large diameter section has a pair of blades with one having longer first pins and the other having shorter second pins. A first oblong cam recess and a second oblong cam recess having a second longer longitudinal axis and a shallower depth than the first recess.
During rotation of the case, the torque of the axis is increased, but the disadvantage of the cited invention is that the applied torque cannot be determined.
U.S. Pat. No. 6,467,547 describes a tool comprising a torque-dampening system. A first portion and a second portion of the tool are operably related by a torsion interface. In one embodiment, the torsion interface includes a plurality of interlaced teeth disposed on the each of the first and second portions. During relative rotation of the first and second portions, the teeth engage and “ride up” on one another, thereby forcing the first and second portions in opposite axial directions. At least one of the portions houses a flow restrictor assembly adapted to restrict fluid flow from one region to another during the axial movement of the portions. In this way, the relative rotation between portions is inhibited or reduced, for this reason the functionality of the tool includes a torque detent, however, a particular torque cannot be determined.
U.S. Pat. No. 6,818,253 describes an hydraulic power tool that in a notch has a power axis associated to the power tool, it also has a transducer adapted for measuring the torque, this transducer is mounted in the notch, or a transducer stationary portion is mounted in contactless relationship with the axis. The tool allows measuring the applied torque, however it isn't possible to preset a particular torque that is going to be applied.
As can be noted, the tools from the prior art don't include an integral regulated or controlled tightening system of manual and autonomous actuating, for previously selecting the torque to be applied.